Many fruit have been exploited for their use in the preparation of juices and purees. These are then commonly used in the preparation of other foodstuffs, often being used in the capacity of a base material, extender or flavouring agent. However, virtually all known juice and puree manufacturing processes have been standardised and based upon conditions optimised for apples. Unfortunately, the fruit of the genus Actinidia (the best known of which is the kiwifruit or Actinidia Chinensis) have their own inherent problems which does not make them amenable to the known prior art processes.
For instance, taking kiwifruit as being representative of most fruit of the genus, the fruit is very high in acidity, chloroplasts (giving the fruit its green colour), enzymes and other components not normally found in any appreciable quantities in other fruits, such as apples. Consequently, kiwifruit does not behave favourably under the conditions used for other fruit.
For example, the pulp of a fruit will readily change colour to straw or brown, a problem which as dogged juice manufacturers as a brown juice product does not appeal to the public. However, discolouration is less of a concern for some product applications, especially where the composition is to be used in the preparation of another product.
However, discolouration is also accompanied by other changes to the nature of the product. Perhaps the most significant of these are the renowned kiwifruit `catch` which is a mild unpleasant feeling left in the throat after consuming some kiwifruit products. The cause of catch has yet to be specifically identified though theories include denaturing of chloroplasts, the presence of components normally residing in the skin and hair of the fruit, oxidation products, the presence of calcium oxalate, reaction products between added and naturally occurring components, as well as various other side reactions. The catch factor, where it appears, can be undesirable as it detracts from the taste and pleasant qualities of any food product. Consequently, kiwifruit has been precluded from use in many areas where it might otherwise be used due to the catch problems which appear to result predominantly from the temperamental nature of the fruit of the genus and their intolerance to the relatively harsh treatment by prior art fruit processing techniques.
A further problem of most prior art processes is that they produce a composition whose qualities merely resemble that of the fruit from which it is desired, and often the resulting product or compositions is poorer in quality than the natural fruit. In many cases, the product or composition is suitable merely as an extender, or as an alternative and more convenient form of introducing fruit into a product. However, it has been discovered during research by the applicant that fruit of the genus Actinidia contain components which can extend the use of a derived puree type composition beyond the normal applications of such compositions.
It is now considered by the applicant that such components are likely to include pectins occurring in the kiwifruit so that a puree type composition derived from the fruit will typically exhibit the unusual ability to thicken upon the application of the shear force and/or aeration. It is also considered that the fibres within the fruit may also contribute to the thickening process. These fibres may be cellulose fibres though it is noted that cellulose fibres will occur in other fruit yet other fruit do not exhibit these properties. Kiwifruit products prepared to date according to the prior art methods, do not exhibit this ability and thus all prior art kiwifruit compositions are unable to be used for some of the applications of the present invention, such as in the use of the thickened composition such as mayonnaise, desserts and ice-cream type products.
It is therefore an object of the present invention to address the problems of the prior art, or at least to provide the public with a useful choice.
Further aspects of the present invention will now be described by way of example only.